1. Field of the Invention
The present invention relates to an ink-jet recording head and an ink-jet recording device.
2. Description of the Related Art
Aqueous ink-jet printers currently available on the market tend to, in principle, use dye inks and pigment inks having viscosities of about 5 cps or, on the high end, about 10 cps. It is known that printing capability can be improved by increasing the ink viscosity in order to: prevent ink from bleeding at the time of impact with the medium; increase optical color density; suppress swelling of the medium by reducing the moisture content; achieve quick-drying features; or obtain a high degree of freedom by completely designing high-quality inks having all of these characteristics.
On the other hand, in order to eject high-viscosity ink, it is necessary to use a mechanism that generates high-output pressure, and this tends to create disadvantages such as increases in cost and head size. Conventionally, a heater is provided separately from the ejector, and a technology is known where the ink viscosity is forcefully lowered at the time of ejecting (e.g., Japanese Patent Application Laid-Open (JP-A) No. 2003-220702 (refer to FIG. 1 and pp. 4 to 6)). Nonetheless, there is a fundamental problem with the aforementioned method in which the ink is heated in that ink deterioration and damage to the duct is accelerated and usable inks are limited to those that do not deteriorate with heat.
Besides the above, a technology has been disclosed where higher viscosity ink is ejected and ink flow in the opposite direction, when discharging the ink, is restrained by a beam-shaped valve (e.g., JP-A No. 9-327918 (refer to FIG. 1 and pp. 8 and 9)).
A technology has been disclosed where buckling bending, by which large deformation can be obtained, is used as a method for increasing the power of the pressure-generating mechanism itself. This technology utilizes a diaphragm-shaped actuator that deforms with the heat-expansion difference with the heat-generating layer (e.g., JP-A No. 2003-118114 (refer to FIG. 3 and pp. 4 and 5)). Further, a technology has been disclosed that uses a cantilevered beam-shaped actuator with a similar configuration (e.g., JP-A No. 2003-34710 (refer to FIG. 13 and pp. 6 to 8)).
An example is shown in FIGS. 10A and 10B of an ink-jet recording head 100 in which an actuator 102 rapidly pressurizes an ink 101 in an ink chamber 106 by deformation (from FIG. 10A to FIG. 10B) whereby the ink is ejected from a nozzle 104 as an ink droplet 108.
Nonetheless, even in the aforementioned related art, it is extremely difficult to stably eject high-viscosity inks, such as those having viscosities greatly larger than 10 cps, i.e., 50 to 100 cps, at ordinary temperature.
In the related art with an ink-jet recording head utilizing an electrostrictive element, it is necessary to use an element provided with rapid rising/falling characteristics in the switching IC. For this reason, these technologies have been extremely expensive.